Ans. b. 1-9 years (Ref: Trachoma Surveillance Annual Report 2008; Park 23/e p308)Screening age for trachoma is 1-9 years.School children are screened and mass treatment with azithromycin is given in areas found to have active trachoma (TF >10% in children aged 1-9 years).Trachoma control includes all the components of the SAFE strategy, which are integrated with other control of blindness activities.Health education is also provided.School children are screened and mass treatment with azithromycin is given in areas found to have active trachoma (TF >10% in children aged 1-9 yearsQ).TrachomaCaused by Bedsonian organism, Chlamydia trachomatis belonging to PLT (Psittacosis, Lymphogranuloma, Trachoma) group.Chlamydia is epitheliotropic and produce intracytoplasmic inclusion bodies called H.P, (Halberstedter Prowazeki) bodies.Source of infection is conjunctival discharge of the affected person.Incubation period is 5-21 daysQ.Clinical picture of trachoma is determined by the presence or absence of infectionQ. Mostly the picture is complicated by secondary infection. Conjunctival signs in TrachomaCongestion of upper tarsal and fornix conjunctivaQConjunctival follicles:Look like boiled sago grains, more common on upper tarsal conjunctiva and fornixQSometimes follicles maybe seen on bulbar conjunctiva (Pathognomic of trachoma)QCentral part of each follicle is made up of mononuclear histiocytes, few lymphocytes and large multinucleated giant cells called Leber's cellsQ.Presence of Leber's cells and signs of necrosisQ differentiate trachoma follicle from other forms of follicular conjunctivitis.Papillary hyperplasiaQConjunctival Scarring: Linear scars present in sulcus subtarsalis is called Arlt's lineQConcretions formed due to dead epithelial cells and inspissated mucus in the depressions called glands of HenleQ.Corneal signs in TrachomaSuperficial Keratitis in upper partHerbert follicles (Typical follicles in limbal areaQ)Pannus:It is infiltration of cornea associated with vascularization in upper partQThe vessels are superficial and lie between epithelium and Bowman's membraneIn progressive pannus, infiltration of cornea is ahead of vascularizationQIn regressive pannus, vessels extend a short distance beyond the area of infiltrationQCorneal ulcer at advancing edge of pannusHerbert pitsQ (oval or circular pitted scars, left after healing of Herbert follicles in limbal area)Corneal opacityGrading of TrachomaMcCatlan's ClassificationStage IIncipient trachoma or stage of infiltration* Hyperemia of palpebral conjunctiva* Immature follicles on superior tarsus* Mild superficial keratopathy and pannusStage IIEstablished trachomaor stage of florid infiltration* Superficial tarsal follicular reaction with mature follicles (IIa)* Marked papillary hyperplasia (IIb)* Pannus formation* Limbal follicles* Superior comeal subepithelial infiltratesStage IIICicatrizing trachoma or stage of scarring* Scarring along with follicles indicating persisting active infectionStage IVHealed trachoma or stage of squeal* Disease has become quiet, so there are no follicles* Squeal include trichiasis, Entropion, corneal opacity, xerosis, blindness, corneal ulcer